Byunghong Lee

By Byunghong Lee and Robert Bob Chang

This chapter has been mainly focused on the development and fabrication of various nanostructured materials for electrochemical energy conversion, specially, third generation (3rd) thin film photovoltaic system such as organic dye or perovskite -sensitized Solar Cells. Enormous efforts have been dedicated to the development of a variety of clean energy, capable of harvesting energy of various forms. Among the various energy forms, electrochemical devices that produce electric energy from chemical energy have received the most attention as the most promising power sources. In the majority of cases, researchers who come from the different background could engage on certain aspects of the components to improve the photovoltaic performances from different disciplines: (i) chemists to design and synthesize suitable donor–acceptor dyes and study structure–property relationships; (ii) physicists to build solar cell devices with the novel materials, to characterize and optimize their performances, and to understand the fundamental photophysical processes; and (iii) engineers to develop new device architectures. The synergy between all the disciplines will play a major role for future advancements in this area. However, the simultaneous development of all components such as photosensitizers, hole transport layer, photoanodes and cost effective cathode, combined with further investigation of transport dynamics, will lead to Photovoltaic cells, 30%. Herein, in this book, with taking optimized processing recipe as the standard cell fabrication procedure, imporant breakthough for each components is achieved by developing or designing new materials, concepts, and fabrication technique. This book report the following studies: (i) a brief introduction of the working principle, (ii) the detailed study of the each component materials, mainly including TiO2 photoanode under the category of 0D and 3D structures, strategies for co-sensitization with porphyrin and organic photosensitizers, and carbon catalytic material via controlled fabrication protocols and fundamental understanding of the working principles of electrochemical photovoltaic cell has been gained by means of electrical and optical modelling and advanced characterization techniques and (iii) new desgined stratages such as the optimization of photon confinement (iv) future prospects and survival stratagies for sensitizer assisted solar cell (especially, DSSC).

Part of the book: Solar Cells

By Rira Kang, Tae-ho Jeong and Byunghong Lee

Perovskites material is in the spotlight as photovoltaic device due to their optical and physical properties. In a short period of time, this organic-inorganic pevskite can achieve about energy conversion efficiencies of 25.6% by anti-solvent and spin-coating based process. In addition, ambipolar carrier transport properties of perovskite materials open up new directions for the high-efficiency thin-film solar cells. Despite its attractive properties in solar cell application, concerned about device stability and the use of lead compounds (APbX3, A = a cation X = halide) with toxicity cause the potential risk for the human body and environment issue. Therefore, the use of a new classed strucutral materials with intrinsic stability and beneficial optoelectronic properties can be considered as a start of the next chapter in pervoksite device. This chapter is structured into two major parts: In section 1, we introduce more stable class of perovskite, A2SnX6, where Sn is in the 4+ oxidation state. A detailed discussion on the ramifications of material structure and chemistry-related challenges is presented for solution processing, along with careful characterization. In section 2, we talk about the direction of development for perovksite materials to be a next chapter of energy source for a green mobility.

Part of the book: Recent Advances in Multifunctional Perovskite Materials